Continued support of the Great Lakes New England (GLNE) Clinical Validation Center (CVC) of the Early Detection Research Network (EDRN) via the U01 mechanism is requested. The GLNE CVC is a highly collaborative, multi-institutional consortium designed to develop, implement and analyze trials for the validation of biomarkers for the early detection of colorectal adenocarcinoma and other Gl malignancies. Over the last 5 years, the GLNE has developed a high quality biosample repository of samples collected from human subjects with colorectal and lower esophageal neoplasias and controls. The GLNE has preliminary characterization of 16 biomarkers for the early detection of colorectal adenocarcinoma and 3 biomarkers for the detection of progression of lower esophageal metaplasia to dysplasia and carcinoma. The GLNE has collaborated with 5 biomarker developmental laboratories, 4 biomarker reference laboratories, the EDRN DMCC, and 5 industrial partners publishing 23 manuscripts including 15 manuscripts collaborating with other EDRN centers. In the next grant period, the GLNE-CVC proposes to 1. To determine the performance of vimentin methylation, galectin-3 ligand, the Exact stool DNA panel, and fecal immunochemical test (FIT) for the early detection of colorectal neoplasia using colonoscopy as the gold standard;2. To determine if vimentin methylation, galectin-3 ligand, Exact sciences stool DNA panel, or any future individual biomarker alone performs better than fecal immunochemical testing for the detection of colorectal adenocarcinoma and high grade dysplasia;3. To determine the screening performance of vimentin methylation in stool, galectin-3 ligand, Exact sciences stool DNA panel, or any future individual biomarker or FIT together for detection of colorectal adenocarcinoma and high grade dysplasia;and 4. To establish an archive of appropriately preserved stool, serum, plasma, urine, and DNA human biospecimens to be used by EDRN investigators for future validation and biomarker discovery research. These aims will be addressed by a multi-institutional consortium of university and community Gl practices recruiting human subjects undergoing screening colonoscopy under a PRoBE compliant protocol. The protocol requires the implementation of detailed standard operating procedures for biosample collection and management and associates these biosamples with EDRN compliant data elements. The data will be managed and analyzed by the EDRN data management and coordinating center. Biosamples will be collected for future biomarker colorectal cancer early detection validation trials and to support EDRN biomarker discovery and prevalidation.